#include<iostream>
#include<iomanip>
using namespace std;
int main()
{
	int n;
	cin >> n;
	while (n--)
	{
		int k = 0;
		cin >> k;
		double max = -1321;
		for (int i = 0; i < k; i++)
		{
			double f;
			cin >> f;
			if (f > max) {
				max = f;
			}
		}
		cout << fixed <<setprecision(2) << max << endl;
	}
	return 0;
}